Well testing apparatus



INVENToR. IV/L/A/ C. M07' Sept. 22, 1959 w, c. ToDT WELL TESTING APPARATUS 4 Filed Sept. l1, 1956 F15 Jaz.

2 Sheets-Sheet 2 Filed sept. 11, 1956 INVENTOR.

#la .4free/vir 2,905,248 WELL TESTING APPARATUS v 4William C. Todt, Odessa, Tex., assignor to Gulf Oil Corporation, Pittsburgh, Pa., a `corporation of Pennsyl- Vania Application vSeptember 11,1956, Serial No. 609,230

4 Claims. v(Cl. d66-142) 'back to the well-head. The mud is a thin slurry ranging Ain density .from slightly higher than .the density of water to two or even more times the density of water. The 'circulation of muds serves several purposes among which are the removal of cuttings and the maintenance of a hydrostatic pressure on the formations penetrated suf- "iicient to prevent blowing out of the well. Thus, the ycirculation of mud conceals oil bearing formations durling the drilling. After drilling to the desired depth it is necessary to packloif the v'formations which are to be tested in order to prevent contamination with liquids from other formations and the drilling mud, and to allow suiiicient reduction of the hydrostatic pressure on the formation to commence flow from the formation to be tested.

When flow is initially started in a well there may be -substantial entrainment of cutting or other solid particles which subject valves inthe testing apparatus to severe Wear or'lodge behind the valves to prevent their operation. Apparatus allowing removal of the valve assembly Vin the well testing apparatus for replacement of the valves withoutremoval of the pack off apparatus which isolates the formation during the testing is desirable. It is 'also desirable to be able to remove the valve assembly and pack off and test a higher formation in the well without removing the packer isolating the lower formation.

This invention resides in apparatus for testing a well 'in which 'a packer is set above the formation to be tested to prevent contamination of fluids from that formation with uids from higher formations and in which a valve r assembly is removably connected to the pack off assemo bly. 'The valve assembly allows displacement of high v'density liquids from the tubing to reduce the hydrostatic pressure on 'the formation to be tested and thereby allow llow to 'commence from that formation.

In the drawings:

Figure la isa longitudinal view, partly in section, of the upper p'art of a well containing the testing apparatus of this invention.

Figure 1b, also partly in longitudinal section, illustrates a portion of the well below that illustrated in vFigure la, and shows the position of the elements of the valve testing apparatus occupied during displacement 'of high density liquids from the tubing of the well.

yFigure lc, also partly in longitudinal section, is a continuation of Figure lb and shows the bottom part of the Well with apparatus for packing off the formation to be tested from'higher formations in the well.

Figure 2 is a longitudinal view, partly in section, of the yapparatus for disconnecting the packer setting apparatus from the packer, and for receiving the valve assembly.

Patented Sept. 22, 1959 r l ji Figure 3 is a longitudinal sectional View of the valve assembly taken at right angles to the sectional view of Figure l with the valves in the position occupied when the well is producing from the formation.

Figure 4 is a horizontal sectional View, along section line IV-IV in Figure 3, showing the passages through the valve assembly for displacement of mud from the tubing.

Referring to Figure lc of the drawings, the formation to be tested is designated generally by reference numeral 10 in the right hand section of the drawings. A packer 12 of conventional design is set against the borehole wall above the formation 10. The testing apparatus of this invention can be used in open hole, as illustrated, or when the well has been cased to the bottom, in which event the formation is tested through perforationsin the casing and the packer 12 is set against the casing. The packer 1-2 has expandable rubber sleeves 14 which are forced against th'e wall of the formation to prevent contamination of fluids produced from formation 10 with fluids in the space above the packer. A packer sub 16 of conventional design having a longitudinal central opening extends downwardly into the central opening in the packer and seals against the inner Wall of the packer to direct the fluids from the formation it) into the testing apparatus of this invention.

The sub 16 is screwed to the lower end of an adaptor 18 which forms an extension of a sleeve 26, illustrated in Figure l'b of the drawings. The valve assembly of the testing apparatus of this invention, indicated generally by reference numeral 22, is removably connected to the sleeve 2b by means of a connector assembly indicated generally by reference numeral 24.

The upper end of the valve `assembly 22 is connected to the lower end of tubing 26 which extends upwardly to the `Well head, as shown in Figure la. The tubing 26 extends upwardly through casi-ng 28 which is cemented at its lower end, as illustrated yat 30, and supported at its upper end in a casing hanger `32. The casing .hanger 32 is supported in a casing head support 34. The upper end of the casing 2S opens into a casing head 36 h'avin'g an outlet 38 for discharging displaced mud. Casing head 36 is closed at its upper end by a cap 40 having a pack- `ing gland 42 mounted on its upper surface. The tubing 26 extends through packing gland 42 and is connected with a suitable source of fluids under pressure, not shown.

Sections .of `the length-of the well have been 'omitted from the drawings to simplify them. rlhe arrangement at the well head is only illustrative, other arrangements being suitable for use without affecting the operation of the apparatus of this invention. For example, a well usually will have surface or conductor cas-ing, not illustrated in the drawings, .surrounding casing `28 at the Well head. In the apparatus shown, a perforated .tube 44 is connected `to the lower end of the packer sub 16 and extends down into` the borehole in the formation to -be tested. The use of a perforated tube is conventional and the lapparatus may operate without the tube 'or with other suitable screening means.

.Referring to Figure 2 of `the drawings, the sleeve 20 is provided with left hand threads 446 at its upper end for connection with a bushing 48 connecting the sleeve with the apparatus 50 for setting the packer. The apparatus for setting the packer is conventional and will consist of the usual drill collars and jars. After the packer 14 has been set, the setting apparatus 50 is turned to the right to break the connection at left hand thread 46 and the setting apparatus is removed from the -well leaving the sleeve 20 connected to the packer sub `16 through the adaptor 18.

Referring to Figure lb, the connector lassembly 24 has a long tubulal stinger 52 extending ldownwardly from the 1ower end of a connector section 51. Sealing rings 54 are mounted in recesses on the outer surface of stinger 52. The dimensions of the stinger 52 are such that the stinger will tit within the sleeve and the sealing rings 54 will engage the inner wall of the sleeve to prevent leakage between the outer surface of the s-tinger S2 and the inner surface yof fthe sleeve 20. The central opening 56 in the stinger 52 thus provides a continuation of the passage lfrom the packer sub. A skirt 58 extends downwardly `from the connector section 51 of the stinger assembly 24 for substantially the same distance as the stinger 52. Skirt 58 provides a guide directing the stinger 52 into the sleeve 20. The arrangement of the sleeve 20 and stinger 52 could be reversed, with the sleeve extending upwardly into the stinger and sealing means then provided on the inner surface of the stinger. It is important, however, that a slidable seal be provided to allow removal of the stinger While leaving `the sleeve in place -in the well.

As illustrated in Figure lb, a bushing 60 is connected to the upper end of the connector section 51. Bushing 60 has a central opening which provides a continuation of the central opening of the stinger. A threaded boss 62 extends from -the upper end of the bushing 60 Ito receive a tubular inlet valve housing 64.

Referring to Figure 3 of the drawings, the housing 64 opens at its upper end into a cylinder 66 connected to the upper end of Ithe bushing 60. A horizontal valve seat 68 is mounted in the housing around the opening therethrough. Valve seat 68 is provided with a tapered surface 70 which opens directly into the central opening through the housing, thereby providing no place for lodging of cuttings or other solid particles on the valve seat. A valve plug 72 within the housing 64 above the valve seat 68 is adapted to engage the tapered surface 70 to prevent flow through the central opening of `the housing. Valve plug 72 moves vertically within the housing 64 in response to the difference in pressure `on its lower and upper surface. The inlet valve consisting of the housing 64, valve seat 70 and valve plug 72 thus prevents flow downwardly from within the cylinder 66 into the bushing 60, and hence, into the formation. In the apparatus illustrated in the drawings, the valve plug is a ball which may be of any suitable material, such `as stainless steel. The vertically moving valve plug and the valve seats forming in eiect a part of the central passage th-rough the valve assembly provide a free acting valve which is not plugged by entrained solids.

Still referring to Figure 3, la by-pass sub 74 is connected to the upper end of the cylinder 66. The by-pass sub 74 is provided with upwardly and downwardly extending sleeves 76 and 78 for connection with the tubing 26 and cylinder 66 respectively. By-pass ducts 80 extend longitudinally through the body `of the by-pass sub 74 -to permit ilow between the cylinder 66 and the tubing 26. In the embodiment illustrated in the drawings six by-pass ducts 80 are provided. A transverse outlet passage 82 extends horizontally through the by-pass sub 74 in 'a manner to `avoid communication with the by-pass ducts 80. In the preferred arrangement shown, the outlet passage 82 extends at substantially right angles to the plane in which the by-pass ducts extend. A socket 84 extending into the by-pass sub 74 from its lower end intersects the outlet passage 82.

An outlet valve housing 86 extends downwardly from the lower surface of the by-pass sub 74. Outlet housing 86 has a central passage 88 which communicates through socket 84 with the outlet passage 82. A horizontal valve seat 90, similar to valve seat 68, is supported within the housing. Above the valve seat 90 is a valve plug 92 operated by the diiference in pressure on the upper and lower surface of the valve plug in a manner similar to valve plug 72. The outlet valve housing 86 opens at its lower end into the cylinder 66. Valve plug 92 and valve seat 90 thus allows flow through the outlet housing 86 and outlet passage 82 when the pressure within cylinder 66 2,905,248. f- A Y 4 is higher than the pressure in the space surrounding the by-pass sub 74 and tubing 26.

After the packer has been set and the packer setting apparatus disconnected in the manner described and removed from the well, the stinger and valve assembly are run into the well on the lower end of tubing. The well contains drilling mud during setting of the packer and running of the valve and connector assembly. The testing apparatus of this invention is run into the well open; hence, the pressure on the inside of the apparatus is the same as on the outside and there is no force tending to collapse the apparatus. In deep wells the pressures encountered are extremely high and would necessitate extremely heavy construction if the testing apparatus were empty when run into the well. The apparatus is lowered into the well until the stinger 52 is seated in the sleeve 20. The packing rings 54 on the outer surface of the stinger provide a tight seal preventing ilow between the stinger 52 and sleeve 20.

After the stinger and valve assembly are in place, the high density liquid in the tubing resulting from it being run into the well open is displaced by introducing water under pressure into the top of the tubing 26. The higher pressure in the cylinder 66 resulting from the application of pressure on the water raises valve plug 92, as shown in Figure l, and mud is displaced downwardly through the tubing and discharged through outlet passage 82. When it is believed that sufficient mud has been displaced from the tubing 26 to reduce the hydrostatic pressure sufiiciently to allow the well to ilow, the pressure at the upper end of the tubing 26 is relieved. If the density of the liquid in the tubing 26 has been rcduced sufficiently for the formation pressure to overcome the hydrostatic pressure, the well will begin to ow. During ow from the formation the valve mechanism will be in the condition illustrated in Figure 3 with valve 72 raised olf the seat 68 and plug 92 forced downwardly against the seat by the high pressure in the space surrounding the tubing.

If the formation pressure is not sufficient to overcome the hydrostatic pressure of the liquid in the tubing 26, the displacement procedure can be repeated by the introduction of water or oil under pressure into the upper end of the tube 26 until all of the mud is displaced from the tubing. If complete displacement of the mud from the tubing fails to reduce the pressure suiciently to allow flow from the formation to commence the usual swabbing technique can be employed.

If, during the testing operation it appears that the valves are leaking or if it should be desired to remove the testing apparatus to test a formation higher in the well, the valve and stinger assembly can be removed without the necessity of pulling the packer. The sealing rings 54 on the stinger 52 slide over the surface of the sleeve 20 when the stinger and valve assembly are pulled from the well. By mounting the sealing rings on the stinger they can readily be replaced if they should be damaged when the stinger and valve assemblies are pulled from the well.

I claim:

1. Well testing apparatus comprising a formation packer adapted to engage the wall of a well above the formation to be tested and separate that formation from formations higher in the well, said packer having a longitudinal central opening through which production from the formation to be tested is delivered, a sleeve extending upwardly from the upper end of the packer, a tubular Stinger open at its lower end and having a central opening extending therethrough, said stinger being positioned in the well with its lower end slidably overlapping the upper end of the sleeve, sealing elements on the stinger engaging adjacent surfaces of the sleeve and stinger to prevent flow therebetween, said stinger being movable vertically relative to the sleeve to allow withdrawal of the stinger without removal of the packer, a hollow cylinder connected at its lower end to the upper end of the stinger, tubing connected to the upper end of the cylinder and extending upwardly in the well, a ow passage from the cylinder into the tubing for the delivery of production from the well into the tubing, an inlet passage extending from the stinger into the cylinder, a one-way inlet valve positioned in the cylinder to control flow through the inlet passage, said valve allowing flow from the stinger through the inlet passage into the cylinder when the pressure in the stinger is higher than the pressure in the cylinder, an outlet passage from the cylinder to the space surrounding the tubing, and a one-way outlet valve mounted within the cylinder and adapted to allow flow through the outlet passage when the pressure in the cylinder is higher than the pressure in the space surrounding the tubing string.

2. Apparatus as set forth in claim l in which the stinger is of smaller diameter than the sleeve and is adapted to move down into the sleeve, and a skirt surrounds the stinger and is spaced therefrom to lit over the outer surface of the sleeve when the stinger and sleeve are in overlapping position.

3. Well testing apparatus comprising a formation packer adapted to engage the Wall of the well above the formation to be tested and separate that formation from formations higher in the well, said packer having a longitudinal central opening through which production from the formation to be tested is delivered, a sleeve extending upwardly from the upper end of the packer and having a longitudinal opening therethrough communicating with the central opening through the packer, a tubular stinger open at its lower end and having a central opening extending therethrough, said stinger tting slidably within the 'sleeve to allow withdrawal of the stinger without removal of the sleeve, sealing elements mounted on the outer surface of the stinger engaging the sleeve to prevent flow between the sleeve and stinger, a hollow cylinder having its lower end connected to the upper end of the stinger and its upper end connected with tubing for delivery of production from the well, an inlet valve housing within the cylinder having a vertical opening extending from the stinger into the cylinder through which production passes from the stinger into the cylinder, a horizontal inlet valve seat surrounding the vertical opening within the inlet valve housing, a valve plug above the valve seat movable in response to difference in pressure above and below the valve plug to allow flow from the stinger into the cylinder when the pressure on the formation is higher than the pressure in the cylinder and prevent ow from the cylinder through the inlet valve housing when the pressure in the cylinder is higher than the pressure on the formation, an outlet valve housing centrally positioned within the cylinder above the inlet valve housing, a vertical central opening extending through the outlet valve housing, an outlet passage from within the cylinder to the space surrounding the cylinder communieating with the upper end of the vertical passage in the outlet valve housing, a horizontal valve seat surrounding the opening within the outlet valve housing, a valve plug above the horizontal valve seat in the outlet valve housing movable in response to difference in pressure on its lower and upper surfaces to allow ilow from the cylinder through the outlet passage and prevent flow from the outlet passage into the cylinder, and ducts by-passing the outlet passage and connecting the cylinder with the tubing. 4. Well testing apparatus comprising a formation packer adapted to engage the wall of the well above the formation to be tested and separate that formation from formations higher in the well, said packer having a longitudinal central opening through which production from the formation to be tested is delivered, a sleeve extending upwardly from the upper end of the packer and having a longitudinal opening therethrough communicating with the central opening through the packer, a tubular stinger open at its lower end and having a central opening extending therethrough, said stinger being positioned in the well with its lower end slidably overlapping the upper end of the sleeve, sealing elements on the stinger engaging adjacent surfaces of the sleeve and stinger to prevent flow therebetween7 said stinger being movable vertically relative to the sleeve to allow withdrawal of the stinger without removal of the packer, a hollow cylinder having its lower end connected to the upper end of the stinger and its upper end connected with tubing for delivery of production from the well, an inlet valve housing within the cylinder having a vertical opening extending from the stinger into the cylinder through which production passes from the stinger into the cylinder, a horizontal inlet valve seat surrounding the vertical opening within the inlet valve housing, a valve plug above the valve seat movable in response to ditference in pressure above and below the valve plug to allow flow from the stinger into the cylinder when the pressure on the formation ishigher than the pressure in the cylinder and prevent flow from the cylinder through the inlet valve housing when the pressure in the cylinder is higher than the pressure on the formation, an outlet valve housing centrally positioned within the cylinder above the inlet valve housing, a vertical central opening extending through the outlet valve housing, an outlet passage from within the cylinder to the space surrounding the cylinder communicating with the upper end of the vertical passage in the outlet valve housing, a horizontal valve seat surrounding the opening within the outlet valve housing, a valve plug above the horizontal valve seat in the outlet valve housing movable in response to difference in pressure on its lower and upper surfaces to allow flow from the cylinder through the outlet passage and prevent flow from the outlet passage into the cylinder, and ducts by-passing the outlet passage and connecting the cylinder with the tubing.

References Cited in the file of this patent UNITED STATES PATENTS 2,124,766 Cox .Tuly 26, 1938 2,368,428 Saurenman June 30, 1945 2,796,133 EnDean `lune 18, 1957 

